Transparency in risk-disproportionate regulation of modern crop-breeding techniques.

Despite over 25 years of safe deployment of genetically engineered crops, the number, complexity, and scope of regulatory studies required for global approvals continue to increase devoid of adequate scientific justification. Recently, there have been calls to further expand the scope of study and data requirements to improve public acceptance. However, increased regulation can actually generate consumer distrust due to the misperception that risks are high. We believe risk-disproportionate regulation as a means to advocate for acceptance of technology is counterproductive, even though some regulatory authorities believe it part of their mandate. To help avoid public distrust, the concept of regulatory transparency to demystify regulatory decision-making should be extended to clearly justifying specific regulatory requirements as: 1) risk-driven (i.e., proportionately addressing increased risk compared with traditional breeding), or 2) advocacy-driven (i.e., primarily addressing consumer concerns and acceptance). Such transparency in the motivation for requiring risk-disproportionate studies would: 1) lessen over-prescriptive regulation, 2) save public and private resources, 3) make beneficial products and technologies available to society sooner, 4) reduce needless animal sacrifice, 5) improve regulatory decision-making regarding safety, and 6) lessen public distrust that is generated by risk-disproportionate regulation.

Risk-Only Assessment of Genetically Engineered Crops Is Risky.

The risks of not considering benefits in risk assessment are often overlooked. Risks are also often evaluated without consideration of the broader context. We discuss these two concepts in relation to genetically engineered (GE) crops. The health, environmental, and economic risks and benefits of GE crops are exemplified and presented in the context of modern agriculture. Misattribution of unique risks to GE crops are discussed. It is concluded that the scale of modern agriculture is its distinguishing characteristic and that the greater knowledge around GE crops allows for a more thorough characterization of risk. By considering the benefits and risks in the context of modern agriculture, society will be better served and benefits will be less likely to be forgone.

Changes in gene expression during male meiosis in Petunia hybrida.

We analyzed changes in gene expression during male meiosis in Petunia by combining the meiotic staging of pollen mother cells from a single anther with cDNA-AFLP transcript profiling of mRNA from the synchronously developing sister anthers. The transcript profiling experiments focused on the identification of genes with a modulated expression profile during meiosis, while premeiotic archesporial cells and postmeiotic microspores served as a reference. About 8000 transcript tags, estimated at 30% of the total transcriptome, were generated, of which around 6% exhibited a modulated gene expression pattern at meiosis. Cluster analysis revealed a transcriptional cascade that coincides with the initiation and progression through all stages of the two meiotic divisions. Fragments that exhibited high expression specifically during meiosis I were characterized further by sequencing; 90 out of the 293 sequenced fragments showed homology with known genes, belonging to a wide range of gene classes, including previously characterized meiotic genes. In-situ hybridization experiments were performed to determine the spatial expression pattern for five selected transcript tags. Its concurrence with cDNA-AFLP transcript profiles indicates that this is an excellent approach to study genes involved in specialized processes such as meiosis. Our data set provides the potential to unravel unique meiotic genes that are as yet elusive to reverse genetics approaches.

The phytopathogen Rhodococcus fascians breaks apical dominance and activates axillary meristems by inducing plant genes involved in hormone metabolism.

SUMMARY Rhodococcus fascians is a Gram-positive bacterium that interacts with many plant species and induces multiple shoots through a combination of activation of dormant axillary meristems and de novo meristem formation. Although phenotypic analysis of the symptoms of infected plants clearly demonstrates a disturbance of the phytohormonal balance and an activation of the cell cycle, the actual mechanism of symptom development and the targets of the bacterial signals are unknown. To elucidate the molecular pathways that are responsive to R. fascians infection, differential display was performed on Nicotiana tabacum as a host. Four differentially expressed genes could be identified that putatively encode a senescence-associated protein, a gibberellin 2-oxidase, a P450 monooxygenase and a proline dehydrogenase. The differential expression of the three latter genes was confirmed on infected Arabidopsis thaliana plants by quantitative reverse transcription polymerase chain reactions, supporting their general function in R. fascians-induced symptom development. The role of these genes in hormone metabolism, especially of gibberellin and abscisic acid, in breaking apical dominance and in activating axillary meristems, which are processes associated with symptom development, is discussed.

Forward genetics and map-based cloning approaches.

Whereas reverse genetics strategies seek to identify and select mutations in a known sequence, forward genetics requires the cloning of sequences underlying a particular mutant phenotype. Map-based cloning is tedious, hampering the quick identification of candidate genes. With the unprecedented progress in the sequencing of whole genomes, and perhaps even more with the development of saturating marker technologies, map-based cloning can now be performed so efficiently that, at least for some plant model systems, it has become feasible to identify some candidate genes within a few months. This, in turn, will boost the use of forward genetics approaches, as applied (for example) to isolating genes involved in natural variation and genes causing phenotypic mutations as derived from (second-site) mutagenesis screens.